The present invention relates to a system for disabling some cylinders of a multi-cylinder internal combustion engine when the engine operates under light load, and more particularly to a method for improving driveability of an automotive vehicle including an internal combustion engine provided with such a system, a clutch, and a manual transmission, by reducing the vibration and/or a shock which would occur upon reengagement of the clutch.
A known cylinder disabling system is used in conjunction with a fuel-injection multi-cylinder internal combustion engine and it comprises an apparatus to cut the supply of fuel to some cylinders when load on the engine is lower than a predetermined load level. In an automotive vehicle having a multi-cylinder internal combustion engine provided with the system as above, a clutch, and a manual transmission, there is the drawback that, since the accelerator pedal of the engine is released upon disengagement of the clutch, causing the engine to operate on its reduced number of cylinders and thus lowering engine torque, a considerably large vibration and/or a shock is often perceived upon depressing the accelerator immediately after re-engagement of the clutch after the transmission has been shifted to a high gear. Another drawback is that there is an unacceptable delay in response to immediate acceleration demand after the transmission has been shifted to a high gear.